Stonehenge is a massive stone monument located on a chalky plain north of the modern-day city of Salisbury, England. Research shows that the site has continuously evolved over a period of about 10,000 years. The structure that we call “Stonehenge” was built between roughly 5,000 and 4,000 years ago and that forms just one part of a larger, and highly complex, sacred landscape.
The biggest of Stonehenge’s stones, known as sarsens, are up to 30 feet (9 meters) tall and weigh 25 tons (22.6 metric tons) on average. It is widely believed that they were brought from Marlborough Downs, a distance of 20 miles (32 kilometers) to the north.
Smaller stones, referred to as “bluestones” (they have a bluish tinge when wet or freshly broken), weigh up to 4 tons and come from several different sites in western Wales, having been transported as far as 140 miles (225 km). It’s unknown how people in antiquity moved them that far. Scientists have raised the possibility that during the last ice age glaciers carried these bluestones closer to the Stonehenge area and the monument’s makers didn’t have to move them all the way from Wales. Water transport through raft is another idea that has been proposed but researchers now question whether this method was viable.
The story of how Stonehenge, and its sacred landscape, was built is evolving rapidly as new archaeological discoveries are made. The IBM Visual and Spatial Technology Centre at the University of Birmingham is using an array of technologies, including ground penetrating radar and magnetometers, to map Stonehenge and its environs. The project has produced an enormous amount of data, which scientists haven’t fully analyzed.
In addition other research projects have also made recent finds, such as evidence for widespread prehistoric hunting and what may be a new road. When the new discoveries are combined with older finds, it shows that Stonehenge was just one part of a complex and constantly changing sacred landscape.
From what scientists can tell, Salisbury Plain was considered to be a sacred area long before Stonehenge itself was constructed. As early as 10,500 years ago, three large pine posts, which were totem poles of sorts, were erected at the site.
Hunting played an important role in the area. Recently researchers uncovered roughly 350 animal bones and 12,500 flint tools or fragments, just a mile away from Stonehenge, the finds dating from 7500 B.C. to 4700 B.C. The presence of abundant game may have led people to consider the area sacred.
Recently researchers have also discovered a massive wooden building, which may have been used for burial rituals. Also, dozens of burial mounds have been discovered near Stonehenge indicating that hundreds, if not thousands, of people were buried there in ancient times. At least 17 shrines, some in the shape of a circle, have also been discovered near Stonehenge.
As time went on the landscape continued to change. Around 5,500 years ago, two earthworks known as Cursus monuments were erected, the longest of which ran for 1.8 miles (3 km).
More construction occurred around 5,000 years ago with postholes indicating that either bluestones or upright timber posts were propped up on the site. Then, around 4,600 years ago, a double circle made using dozens of bluestones was created at the site.
By 4,400 years ago, Stonehenge had changed again, having a series of sarsen stones erected in the shape of a horseshoe, with every pair of these huge stones having a stone lintel connecting them. In turn, a ring of sarsens surrounded this horseshoe, their tops connecting to each other, giving the appearance of a giant interconnected stone circle surrounding the horseshoe.
By 4,300 years ago, Stonehenge had been expanded to include the addition of two bluestone rings, one inside the horseshoe and another between the horseshoe and the outer layer of interconnected sarsen stones.
Construction at Stonehenge slowed down around 4,000 years ago. As time went on the monument fell into neglect and disuse, some of its stones fell over while others were taken away. [In Photos: A Walk Through Stonehenge]
Recently, archaeologists found an interesting connection between the earlier Cursus monuments and the later Stonehenge. They found that the longest Cursus monument had two pits, one on the east and one on the west. These pits, in turn, align with Stonehenge’s heel stone and a processional avenue.
“Suddenly, you've got a link between [the long Cursus pit] and Stonehenge through two massive pits, which appear to be aligned on the sunrise and sunset on the mid-summer solstice," said University of Birmingham archaeologist Vincent Gaffney, who is leading the project to map Stonehenge and its environs.
Why was Stonehenge constructed?
While there have been many theories as to why Stonehenge was constructed, recent discoveries indicate that Stonehenge’s landscape was a sacred area, one that underwent constant change.
“It's part of a much more complex landscape with processional and ritual activities that go around it," Gaffney told Live Science, noting that people may have traveled considerable distances to come to Stonehenge.
One new theory about Stonehenge, released in 2012 by members of the Stonehenge Riverside Project, is that Stonehenge marks the “unification of Britain,” a point when people across the island worked together and used a similar style of houses, pottery and other items.
It would explain why they were able to bring bluestones all the way from west Wales and how the labor and resources for the construction were marshaled.
In a news release, professor Mike Parker Pearson of the University of Sheffield said that "this was very different to the regionalism of previous centuries. Stonehenge itself was a massive undertaking, requiring the labour of thousands to move stones from as far away as west Wales, shaping them and erecting them. Just the work itself, requiring everyone literally to pull together, would have been an act of unification."